Your Corner Weight Figures Please
Discussion
Getting the cross weight as close to 50% is the key, spread the load.
Richard did you have figures for the weights on each wheel with you in the car before Mat did his magic. Did he adjust any corner heights to get those figures?
No thrust angle etc
pretty parallel on the toe, nice fast and not so rear endy I'd say!
Richard did you have figures for the weights on each wheel with you in the car before Mat did his magic. Did he adjust any corner heights to get those figures?
No thrust angle etc
pretty parallel on the toe, nice fast and not so rear endy I'd say! 
I have heard of corner weighting but do not understand the details. The accepted set-up of the Chimaera is tail (measured at cnr of rear outriggers) higher than nose (measurement at cnr of front outriggers)
My thoughts are that the heavier bits are middle to front and a nose down set-up would not balance out total weight to the corners?
My thoughts are that the heavier bits are middle to front and a nose down set-up would not balance out total weight to the corners?
You'd be surprised, Graham.
Open the bonnet, stand beside the car, look where the wheels are, look where the engine is, visualise where the gearbox is and yourself in the driver's seat, then you can see that the weight in the car is mainly between the axles, and evenly distributed front to back.
A corner weighting is done by placing a computerised scale under each wheel, and then adjusting the suspension so that the scales all read as equally as possible, by raising one corner up and lowering another one down - slightly.
It's why my car always felt more balanced on track with a passenger on board, corner weighting compensates for the unbalance caused by the lack of one.
Open the bonnet, stand beside the car, look where the wheels are, look where the engine is, visualise where the gearbox is and yourself in the driver's seat, then you can see that the weight in the car is mainly between the axles, and evenly distributed front to back.
A corner weighting is done by placing a computerised scale under each wheel, and then adjusting the suspension so that the scales all read as equally as possible, by raising one corner up and lowering another one down - slightly.
It's why my car always felt more balanced on track with a passenger on board, corner weighting compensates for the unbalance caused by the lack of one.
Edited by QBee on Tuesday 18th August 22:32
Has anyone got the missing measurements to complete this?
http://www.hypercoils.com/spring-calculator
I've ended up fudging some approximate figures in and it's telling me I need at least 385lbs springs on the rear rather than my 325lbs ones that apparently came standard with Gaz Gold Pros.
It also seems to suggest a standard Chimaera (without my extra 30gk LPG weight) would benefit from 365lb springs at the rear.
Does Gaz really give you 325lb rear springs when you buy a set of Chimaera Gaz Gold Pros?
If so there's little wonder I'm bottoming out from time to time
http://www.hypercoils.com/spring-calculator
I've ended up fudging some approximate figures in and it's telling me I need at least 385lbs springs on the rear rather than my 325lbs ones that apparently came standard with Gaz Gold Pros.
It also seems to suggest a standard Chimaera (without my extra 30gk LPG weight) would benefit from 365lb springs at the rear.
Does Gaz really give you 325lb rear springs when you buy a set of Chimaera Gaz Gold Pros?
If so there's little wonder I'm bottoming out from time to time
Edited by ChimpOnGas on Tuesday 18th August 22:58
QBee said:
You'd be surprised, Graham.
Open the bonnet, stand beside the car, look where the wheels are, look where the engine is, visualise where the gearbox is and yourself in the driver's seat, then you can see that the weight in the car is mainly between the axles, and evenly distributed front to back.
A corner weighting is done by placing a computerised scale under each wheel, and then adjusting the suspension so that the scales all read as equally as possible, by raising one corner up and lowering another one down - slightly.
It's why my car always felt more balanced on track with a passenger on board, corner weighting compensates for the unbalance caused by the lack of one.
5
Corner weighting should always be done allowing for weight of driver only ...even when not track focused , as you will only ever drive at 10/10 on you're ownOpen the bonnet, stand beside the car, look where the wheels are, look where the engine is, visualise where the gearbox is and yourself in the driver's seat, then you can see that the weight in the car is mainly between the axles, and evenly distributed front to back.
A corner weighting is done by placing a computerised scale under each wheel, and then adjusting the suspension so that the scales all read as equally as possible, by raising one corner up and lowering another one down - slightly.
It's why my car always felt more balanced on track with a passenger on board, corner weighting compensates for the unbalance caused by the lack of one.
5
Edited by QBee on Tuesday 18th August 22:32
Years ago Joolz set me up with a set of springs standard +20%.
This was because my car was bottoming out on rough roads.
275/325+20% is equal to approx 330/390. I recollect he gave me 350/400 springs.
This completely eliminated the bottoming out. These were fitted on a standard set of ProTech suspension units. This was well before I started doing track days. The ride I thought was excellent.
This was because my car was bottoming out on rough roads.
275/325+20% is equal to approx 330/390. I recollect he gave me 350/400 springs.
This completely eliminated the bottoming out. These were fitted on a standard set of ProTech suspension units. This was well before I started doing track days. The ride I thought was excellent.
phazed said:
Years ago Joolz set me up with a set of springs standard +20%.
This was because my car was bottoming out on rough roads.
275/325+20% is equal to approx 330/390. I recollect he gave me 350/400 springs.
This completely eliminated the bottoming out. These were fitted on a standard set of ProTech suspension units. This was well before I started doing track days. The ride I thought was excellent.
Thanks Peter, thats very helpful This was because my car was bottoming out on rough roads.
275/325+20% is equal to approx 330/390. I recollect he gave me 350/400 springs.
This completely eliminated the bottoming out. These were fitted on a standard set of ProTech suspension units. This was well before I started doing track days. The ride I thought was excellent.
I'm still waiting for someone to conclusively tell me what spring rates you get with a standard set of Gaz Gold Pros but it's looking increasingly likely I will need 400lbs springs on the front and 375lbs on the rear to help cope with by extra 30kg at the back and stop the bottoming out.
I haven't corner weighted my car yet and it needs doing, but fag packet maths tells me my weight distribution has shifted from the standard Chimaera setup of 50:50 to a 45:55 rear weight bias.
To me my car clearly handles better that way which is odd when we are constantly told by the car making industry 50:50 is optimal, so I did some research on weight distribution and it would seem the truth is some rear weight bias on a rear wheel drive car is actually what you want.
Apparently the whole 50:50 thing is somewhat of a myth, yes 50:50 is optimal for neutral steering when the car is moving through a fixed radius at a fixed speed but for optimal handling, traction and braking performance you actually want roughly 55% of the weight at the rear & 45% over the front.
Indeed it would seem race cars are typically set up to carry 40% of their weight at the front and 60% to the rear.
Ok so a Chimaera is a road car not a race car so I then looked at a few road cars we all know handle exceptionally well to see what weight bias they run, the results are rather interesting.
1. Caterham R400 - Front 46% - Rear 54%
2. Lotus Elise - Front 39% - Rear 61%
3. Caparo T1 - Front 40% - Rear 60% (actually more of a race car this one)
4. Porsche Boxter - Front 46% - Rear 54%
5. Porsche 911 - Front 38% - Rear 62%
6. Lotus Evora - Front 38.7% - Rear 61.3%
7. Ferrari 599 GTB Fiorano - Front 47% - Rear 53%
8. Dave's 'Ol Gasbag' - Front 45% - Rear 55%
Car 8 aside it seems pretty conclusive that a nod towards a rear weight bias has been intentionally dialed into many of the worlds best handling cars, it certainly seems we've all been duped into thinking the 50:50 figure is optimal.
We also know a Chimaera or Griffith can get a bit lively at the rear, these pages are often filled with people telling tales of sudden snap over steer and wayward rear end scary moments.
Ok so in my case 'Ol Gasbag' only chucks out 250 Shetlands, but before the LPG conversion even I had a few such moments, however now the weight bias has been shifted back by adding the gas bottles over the rear axle line the car feels so much more planted.
Obviously a vehicle's center of gravity and its point of polar inertia also needs to be factored in but even without these figures to hand and looking at my above weight distribution list of great handling cars there certainly seems to be a very strong body of evidence that supports pushing the weight back from the Chimaera's standard 50:50 setup to something closer to 45:55.
Some more interesting watching & reading here that seems to support the case for some rear weight bias:
https://www.youtube.com/watch?v=vJhhUQ4OpLA
http://automotivethinker.com/chassis/stop-and-weig...
http://www.edmunds.com/car-reviews/top-10/top-10-a...
https://en.wikipedia.org/wiki/Automobile_handling
Alun, no I didn't have any figures or information before Mat set things up, he weighed everything there. The only thing he said was that my tyre company had done a great job setting the tracking up,
Dave, just for interest I'm on Nitron Racing Red shocks ( about 8 years old I think) and 325lb rear & 400lb front Eibach springs. I will be sending them off to Nitron this winter for a service & possibly fit new, maybe slightly stiffer springs.
Dave, just for interest I'm on Nitron Racing Red shocks ( about 8 years old I think) and 325lb rear & 400lb front Eibach springs. I will be sending them off to Nitron this winter for a service & possibly fit new, maybe slightly stiffer springs.
Richard 858 said:
Here you go Dave
Hi Richard, can you explain why your car is a bit heavier than I'd expect?TVR Chimaera: 1060Kg
8 gallons of petrol: 26kg
Total: 1086kg
So where's the extra 142kg coming from?
Ok so the average TVR driver probably weighs in at a healthy 84kg but that still leaves 58kgs?
Your supercharger and intercooler surely can't weigh 58kgs?
What am I missing here?
Richard is tall, I would estimate him around the 90-95kg mark. (Thank god he's not female!)
My car has always been nearer 1100 kg. are we sure the 1060 includes oil and water?
And he has added inter cooler, oil cooler(s), supercharger, pipe work, and I think he has an extended baffled sump, which also means another 4-5 litres of oil.
Plus 5kg of wax from all the polishing
My car has always been nearer 1100 kg. are we sure the 1060 includes oil and water?
And he has added inter cooler, oil cooler(s), supercharger, pipe work, and I think he has an extended baffled sump, which also means another 4-5 litres of oil.
Plus 5kg of wax from all the polishing
QBee said:
Richard is tall, I would estimate him around the 90-95kg mark. (Thank god he's not female!)
My car has always been nearer 1100 kg. are we sure the 1060 includes oil and water?
And he has added inter cooler, oil cooler(s), supercharger, pipe work, and I think he has an extended baffled sump, which also means another 4-5 litres of oil.
Plus 5kg of wax from all the polishing
Makes sense, to be honest with just 430 HP & 425 Ft.Lbs I'm surprised it even moves at all with all the lard My car has always been nearer 1100 kg. are we sure the 1060 includes oil and water?
And he has added inter cooler, oil cooler(s), supercharger, pipe work, and I think he has an extended baffled sump, which also means another 4-5 litres of oil.
Plus 5kg of wax from all the polishing
After all at 1228kgs Richards car is only dishing out about 350hp per ton, that's just fractionally better than quite slow stuff like the truly feeble Lamborghini Murcielago.
Tut tut Richard, you really must try harder mate
Very good chaps 
All Anthony's assumptions are correct although I only had the standard sump at the time. For accuracy I've just jumped on the scales and go 93kg. Other than the supercharger mods was running 16" Imolas all round, 225/45 fronts & 245/45 rears roof on, all fluids normal etc., etc. no other ideas but after I've got the MBE run in & remapped I promise to try & improve my power to weight ratio !!!
All Anthony's assumptions are correct although I only had the standard sump at the time. For accuracy I've just jumped on the scales and go 93kg. Other than the supercharger mods was running 16" Imolas all round, 225/45 fronts & 245/45 rears roof on, all fluids normal etc., etc. no other ideas but after I've got the MBE run in & remapped I promise to try & improve my power to weight ratio !!!
Richard 858 said:
Very good chaps
All Anthony's assumptions are correct although I only had the standard sump at the time. For accuracy I've just jumped on the scales and go 93kg. Other than the supercharger mods was running 16" Imolas all round, 225/45 fronts & 245/45 rears roof on, all fluids normal etc., etc. no other ideas but after I've got the MBE run in & remapped I promise to try & improve my power to weight ratio !!!
All Anthony's assumptions are correct although I only had the standard sump at the time. For accuracy I've just jumped on the scales and go 93kg. Other than the supercharger mods was running 16" Imolas all round, 225/45 fronts & 245/45 rears roof on, all fluids normal etc., etc. no other ideas but after I've got the MBE run in & remapped I promise to try & improve my power to weight ratio !!!
Ok so I've gone with a pair of 400lbs springs from the guys at the Gaz factory, for £66.00 delivered it seemed like a no-brainer.
'Ol Gasbag' is sitting down at the Lloyd boys place right now while they fit my new super duper Hana Gold LPG injectors and a few other bits and bobs, so I got Gaz to send them there.
Lloyd Specialist Developments have corner weighting scales so for the first time we'll truly find out what the old girl weighs since I gave her a heavier rear end.
More interestingly we'll be able to see how the weight distribution has genuinely changed, rather than me just guessing based on (in fairness) some pretty straightforward and known mass additions.
Will she be a the 45% front to 55% rear bias I'm expecting, or will it be more like 40/60 in favor of the rear, TBH with those two heavy gas cylinders in there it could easily go 40/60?
Either way we can make a few adjustments and get those 400lb springs on the back which I'm confident will solve the bottoming out issue for the time being, what I am slightly concerned about is the ride quality being too harsh but I guess we can fiddle a bit with the damper rates to dial it in as best we can.
Will my oddball 400lb front and 400lb rear springs work?
Well perhaps not on a standard petrol 50:50 Chimaera, but I'm hoping it'll be just the ticket for my fat bottomed girl
Watch this space
'Ol Gasbag' is sitting down at the Lloyd boys place right now while they fit my new super duper Hana Gold LPG injectors and a few other bits and bobs, so I got Gaz to send them there.
Lloyd Specialist Developments have corner weighting scales so for the first time we'll truly find out what the old girl weighs since I gave her a heavier rear end.
More interestingly we'll be able to see how the weight distribution has genuinely changed, rather than me just guessing based on (in fairness) some pretty straightforward and known mass additions.
Will she be a the 45% front to 55% rear bias I'm expecting, or will it be more like 40/60 in favor of the rear, TBH with those two heavy gas cylinders in there it could easily go 40/60?
Either way we can make a few adjustments and get those 400lb springs on the back which I'm confident will solve the bottoming out issue for the time being, what I am slightly concerned about is the ride quality being too harsh but I guess we can fiddle a bit with the damper rates to dial it in as best we can.
Will my oddball 400lb front and 400lb rear springs work?
Well perhaps not on a standard petrol 50:50 Chimaera, but I'm hoping it'll be just the ticket for my fat bottomed girl
Watch this space
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